Quartz and fused silica have many very desirable material properties, including: high quality factor, high stiffness, chemical inertness, high thermal stability, small visco-elastic losses, low thermal expansion, exceptionally good thermal shock resistance, low dielectric constant and low dielectric losses, good visible and UV transparency, low thermal conductivity, and many others, making these materials excellent choices for many MEMS, micro-mechanical, microelectronic, nanotechnology and photonic applications. Additionally, quartz is a crystalline form of silicon dioxide and therefore is a piezoelectric material making it a great material choice for sensor, actuator, and electronic applications. Likewise glass (silicon dioxide), whether it is pure or contains additives or dopants, and regardless of its crystal structure, also has many desirable properties for MEMS, microelectronic, nanotechnology and photonic device applications, such as low thermal, low electrical conductivity, and good stability.
Consequently, these materials are very attractive for many important commercial and defense applications, including resonators, gyroscopes, oscillators, microbalances, accelerometers, and many others in microelectronics, microsensors, MEMS, micro-mechanical, nanotechnology, and photonic technologies. However, the fabrication technologies to shape and form these materials have been mostly limited to 19th century-based technologies, such as crystal cutting, grinding, and wet etching techniques. While plasma etching of silicon dioxide has been around for several years, this technology has been limited to depths of a few microns or less, very limited aspect ratios, and typically non-vertical sidewalls of the etched features. Consequently, the ability to make deep, small-dimensioned devices and device features with high aspect ratio and vertical etched sidewalls in these important materials has not been available until the invention disclosed herein.